This invention relates to improvements in methods of and in apparatus for stacking sheets of paper and the like, and more particularly to improvements in methods of and in apparatus for converting one or more elongated streams or flows of partially overlapping or non-overlapping sheets or panels into one or more series of stacks of fully overlapping sheets or panels. Such methods and apparatus include the step of or the means for moving and guiding successive foremost sheets or panels (hereinafter called sheets) of each stream or flow (hereinafter referred to as stream) downwardly upon arrival at a stacking or gathering station (hereinafter called stacking station) or at the respective stacking station so that the descending sheet(s) comes or come to rest upon the immediately preceding (already stacked) sheet(s) to thus become part of a single stack or of the respective stack of two or more simultaneously gathered stacks.
Methods or apparatus of the just outlined character are carried out or constructed and assembled in such a way that each freshly delivered sheet is spaced apart from the immediately preceding (i.e., already stacked) sheet in order to avoid interference between such sheets at the stacking station. As used herein, the expression “sheet” is intended to encompass or denote sheets or panels or plates which are made of paper as well as sheets, plates, panels or foils made of metallic or plastic materials, mats and/or others. Such sheets can be obtained by subdividing a running strip into a single series of partly overlapping (imbricated) or non-overlapping sheets of a desired size and/or shape, or by splitting a wide panel into two or more strips and by thereupon utilizing one or more transverse cutters to subdivide each strip into a series of partially overlapping or non-overlapping sheets.
Apparatus of the class to which the present invention pertains are disclosed, for example, in commonly owned U.S. Pat. No. 5,397,120 granted Mar. 14, 1995 to Friedrich Schulz et al. for “APPARATUS FOR STACKING SHEETS”. The patented apparatus is constructed and assembled to gather paper sheets (26) or the like into piles or stacks (52) and employs a vertically movable carrier or platform (16) with associated endless belt or band conveyors (23, 24), a stop (21) for the front edges of successive oncoming sheets, and a rigid elongated rod-like deflector (31) which is adjacent the stop. A ramp (37) is provided to direct successive sheets to the stacking or gathering station and is provided with a window (38) for the lower reaches or stretches of the belt conveyors. The patented apparatus operates satisfactorily, especially at a median or at a relatively low speed and if the material of the sheets can stand reasonable deforming stresses, especially in the regions of the leaders (i.e., front end portions) of sheets approaching the stacking station.